


Collision Course

by KatStark



Category: Supernatural
Genre: Butt Plugs, Consensual Underage Sex, Dirty Talk, Hand Jobs, M/M, Mentions of het, Sibling Incest, Wincest - Freeform
Language: English
Status: Completed
Published: 2014-08-03
Updated: 2014-08-03
Packaged: 2018-02-11 13:23:56
Rating: Explicit
Warnings: Underage
Chapters: 1
Words: 4,118
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/2069847
Author URL: https://archiveofourown.org/users/KatStark/pseuds/KatStark
Summary: <blockquote class="userstuff">
              <p>Summary: Dean decides to tell Sam all about his date. In extremely vivid detail. It changes everything.</p>
            </blockquote>





	Collision Course

**Author's Note:**

> Author's Note: Written for August's smpc. This kind of boundary-crossing story is one of my favourite kinds of Wincest and this particular bunny has been sitting in my ideas folder for quite a while. I'm happy my muse finally decided to let me get further than an outline. Thanks, as always, to my amazing betas deansdirtybb and sleepypercy. Your enthusiasm and assistance are an invaluable part of my writing process and I owe you so much.

Sam was studying at the kitchen table when Dean shoved in through the door. It slammed shut behind him, and he shot Sam a cocky grin and nod when the younger Winchester glowered at the disturbance. Dean grabbed a beer from the fridge and then threw himself over the arm of the couch to land bouncing on the cushions.

 

He sang happily to himself as he sipped and then winked at Sam when Sam looked over, eyes wide with irritation at the noise. Dean merely smirked and then pretended to lock his lips, unlocking them again to sip his beer.

 

Sam lasted about five minutes of Dean's ridiculous version of keeping quiet: tapping his fingers and bouncing his knee until the ancient springs in the couch squeaked. He'd managed to develop a complex rhythm between the two when Sam caved.

 

Sam slammed his textbook closed. "Okay, fine. What?"

 

"I don't know what you mean, Sammy." Dean gave his brother his patented innocent look, guaranteed to melt the hearts of diner waitresses across the country.

 

Sam stared at Dean pointedly, nostrils flaring in irritation, and then Sam deliberately picked up his pen and began opening his book again.

 

"Okay." Dean relented. He was clearly too excited to share his news and wasn't going to risk missing the opportunity to do so by torturing Sam too long.

 

"You know how I've gone out with that girl Christine a couple times, right? Such a good girl, preacher's daughter and all that. But she's got those big, beautiful..." Dean held his hands up to indicate cupping a pair of large breasts, but Sam just glared and made a 'speed it up' gesture with his hands.

 

Dean looked sadly disappointed by Sam's lack of enthusiasm, but he licked his lips and kept going. "Fine, not a breast man, okay. Well, we were parked out on Old Hill Road tonight, and she'd finally let me release those rose-tipped beauties from her bra, and I was licking and suckling one and then the other of those perfect tits as I worked my hand down between her legs."  Dean paused for a sip and watched as Sam shifted in his seat.

 

Sam frowned at his brother. "Gross, Dean. I don't wanna hear about your exploits." But a blush was beginning to rise in his cheeks and he had clearly forgotten all about his homework.

 

Dean just smirked until Sam rolled his eyes and Dean continued, "Now, up to this point, she'd only let us do a little bit of grinding, but I could tell she was loving the feel of my mouth on her tits, sighing and moaning, and clawing at my back and I knew she wasn't as innocent as she'd been playing.

 

"When I started slowly sliding my hand up under her skirt, she stopped me just before I reached her pussy."

 

The kitchen chair screeched across the floor as Sam shifted again, his shoulders tensing, and the blush spreading to his ears. When he noticed Dean noticing, he made an 'I don't care' face, which Dean didn't believe for a second.

 

Dean grinned. "So, I'm about to finally get to dip my fingers in that sweet pussy when she clenches her thighs tight and says that she's saving herself for marriage. I have to force myself to smile as she shows me the pledge charm she wears on her necklace every day to keep Jesus and her promise 'Close to her heart.'

 

"I'm disappointed, but I keep stroking her warm thigh and say, "Of course, Sweetheart. But I just wanna make you feel good. What if I just use my fingers or my mouth?" and I slide my fingers just that tiny bit further to stroke along the elastic of her panties as I lay kisses across her soft belly."

 

"Dude," Sam interjected. "If you interrupted my studying to tell me about how you just got cock-blocked by Jesus…"

 

Dean gave Sam a huge shit-eating grin and then took a long pull on his beer. His smugness so palpable it was like there was a third person in the room with them. A person Sam wanted to punch in the face.

 

"Can I finish?" Dean asked and Sam huffed out a frustrated breath, raising his eyebrows in assent.

 

"Well," Dean said, "she opens her legs for me and I slide my fingers under the elastic, and as I just start stroking her warm, slick pussy, she says, "We could do it in the butt, though. I'm still a virgin if we just do it in the butt."

 

Sam was sitting completely still now, his eyes locked on Dean.

 

"So, I'm trying not to cream my jeans there and then. The sweet preacher's daughter is spread out across the back seat of the Impala, asking me to fuck her ass, and I'm ready to mouth-kiss Jesus thank you.

 

"I pull off her pink, silky thong and strip down to my underwear and then I eat her pussy for a while. She makes the most adorably surprised sound when she comes on my tongue. My face is absolutely dripping with her and I slide one finger back to graze over her asshole."

 

Sam made a tiny sound in the back of his throat and Dean's green eyes swung over to fix on those of his younger brother. He'd been teasing and trying to rile the 15-year-old up, but he was surprised to see Sam's shoulders rising and falling with heavy breaths, his pupils dilated so large they about covered his changeable irises, and his bottom lip plump and pink from where he'd been biting it.

 

Dean stood and walked toward the kitchen, shaking his empty bottle at Sam's questioning expression, and chuckling as Sam squirmed in his seat, trying to adjust his obvious erection. Dean grabbed a new bottle from the mini-fridge and moved to the table.

 

"Now, where were we?" Dean asked, stepping up behind Sam as he cracked his second beer, placing the cap on the table next to Sam's discarded pen. "Oh yes. I've got my tongue buried deep in her snatch and I start just barely pressing a pussy-slick finger into her ass when whaddya know, it slips right inside.

 

"Turns out, Christine wore a plug all afternoon before our date and got herself all wet and open for me beforehand."

 

Sam was breathing even harder now, and Dean leaned in close, his hands on the table on either side of Sam, pressing the younger man forward as small whimpers escaped his throat. Dean's own voice was ragged and cracked with arousal.

 

"So, she's all open and eager for my fingers, all pretence gone now. She rolls over onto her hands and knees and sticks her ass high in the air. I'm frantically trying to get a condom on and get lubed up when she starts begging me to fuck her ass, and now I'm just desperately trying not to come before I get a chance to.

 

"And oh, Sammy," Dean groaned, his breath gusting over Sam's ear. "You can't imagine how sweet and tight her ass was for me. Even through the condom, she was so hot and smooth, and I held those perfect bouncing tits as I fucked her so deep. And she's moaning and thrashing, and bucking her hips.

 

"And then I'm coming, and I'm almost blind with the pleasure as she clenches tight, milking every last drop from my balls."

 

Dean reached down with his last words and squeezed Sam's dick. Sam arched off the seat and came in his pants, his older brother's mouth hot against his throat.

  
  
  


Sam felt his brother's eyes on him for the next few days following Dean's storytime, and he caught himself watching Dean in return. They didn't talk about it - of course they didn't, they're Winchesters - but there was a strange energy between them.

 

They'd always had a tactile relationship, but after their shared moment the previous week, there'd been more wrestling for the remote, more lounging around the motel room in their underwear, more brushing against the other one when they crowded at the bathroom sink to brush their teeth. It was like the world's most complicated game of chicken.

  
  


Dean staggered to the kitchen late one Saturday morning in his boxer briefs, eyes barely open and hair sticking up in an impressive bed head. He grunted at Sam and poured himself a cup of coffee, gulping down a good half of the contents before looking at Sam, who was taking notes for an essay.

 

"Dad gone already?"

 

"Yep. Should be back tomorrow night, if all goes well."

 

Dean nodded and then noticed what Sam was working on. "Such a geek," Dean admonished. "Shouldn't you be doing something normal on a Saturday morning, like watching cartoons. Or porn.  Someone didn't raise you right."

 

Sam shook his head incredulously.

 

Dean leaned back to stretch his lower back and Sam can't help but follow the long, lean muscles of Dean's stomach down to where Sam could spot the faint outline of Dean's dick.

 

"My eyes are up here, Sailor." Dean's words broke through Sam's reverie, and he met Dean's laughing gaze guiltily. Dean winked and leaned one elbow on the counter, crossing his long legs casually.

 

"I went out with Christine again last night." Sam's audible intake of breath surprised them both but Dean quickly continued, "And while I was licking her perfect, pink asshole until she screamed and shuddered on my tongue, begging me to fuck her, I got her to tell me about how she gets herself ready for dates.

 

"Turns out the preacher's baby girl has got a thing for gay porn and discovered that Tumblr isn't blocked by their Net Nanny so she can look at all the raunchy ass-sex she can get her hands on. Did you know there was porn on Tumblr?"

 

"Um, yeah," Sam answered and Dean grinned cheekily.

 

"So she gets out the bottle of moisturizer next to her bed that is actually filled with lube and starts doing small, slippery circles with her index finger around her hole until she can just barely sneak it inside the outer ring. Then she likes wriggling it ever so gently until the second ring just opens up and welcomes her inside."

 

Dean paused, then made as if to walk away. "Actually, you're probably not interested in any of this, Sammy."

 

"No." Sam's voice cracked on the single syllable so he cleared his throat and tried again, but his voice still shook. "No, no Dean. I don't mind. You can tell me about your night."

 

Dean looked at Sam appraisingly and then approvingly and Sam could see that Dean's boxers were starting to bulge where his cock was filling.

 

"Once she's got one finger in she likes to lie in whatever position the guy on her laptop screen is in and fuck that finger in and out until it's easy and she's craving more."

 

Sam's sweats were tented obscenely by this point and he was about to turn his body away from Dean's view when his brother shook his head minutely, his own erection obvious. Sam let out a shaky breath and stayed where he was.

 

"So, when one finger isn't enough, she slicks up a second and slides that one in beside the first. It's always weird at first, she says, the stretch burns but she knows it's gonna feel so good. She fucks two in and out, maybe changing position again with the porn guys.

 

"If she's got a lot of time, she keeps going with three, and sometimes four fingers, depending on who she's going out with." Dean lifted his hand to his mouth conspiratorially. "I was a four finger, she could just tell."

 

Sam rolled his eyes at Dean's smirk but then dropped to Dean's crotch, and he couldn't argue with her assessment.

 

Dean's tongue darted out to wet his bottom lip. "Once she's all open, she lubes up one of her plugs and slides it home. She doesn't like to get off yet because she loves how desperate she gets and it makes the sex so much better later. She says she loves how dirty she feels as she does her chores or has dinner with her parents while her ass is all stuffed full."

 

Sam was staring open-mouthed at Dean when his brother finished his story.

 

"Well," Dean said, after a pause. "I'm gonna go shower and take care of 'this.' He gestured to his straining underwear. "But I almost forgot. I got you something. I don't know why, but it just screamed Sammy." He grabbed a paper bag from his backpack and tossed it on the table next to Sam's forgotten essay.

 

Sam had to wait until he heard sound of the shower running before his hands had finished shaking enough to open the bag. Inside were a bottle of lube and a slim plug.

  
  
  


Dean was stretched out on the couch watching Dr. Sexy when Sam came out of the bedroom later that afternoon. His eyes widened at Sam's awkward gait.  "You're wearing it, aren't you?" he asked, his voice breathy with excitement.

 

"Yeah," Sam whined, his face contorting with each step.

 

Dean dropped his feet to the floor and patted the seat beside him. Sam sat gingerly, whimpering loudly as the pressure from the cushion shifted the plug inside him.

 

Dean was staring at his younger brother unabashedly. "How does it feel?" he whispered, leaning toward Sam, the weight change on the cushions causing Sam to whimper again.

 

"I dunno," Sam replied, his words halting. "Weird. Kinda uncomfortably stretchy, but sometimes it hits something that feels really fucking good, almost too good, you know?"

 

"Fuck," Dean breathed. "Did you come?" Dean shouldn't be asking, shouldn't have started any of this, but now that he had, there was no stopping it.

 

"No," Sam answered, obviously too strung out to be embarrassed. "I mean, I did. Before." He shifted his hips a little and grunted like his breath was knocked out of him. "I thought it would relax me."

 

"Fuck," Dean repeated and then cleared his throat. "Did you wanna? I mean, I've still got the hack codes for the adult station." He paused and rubbed the back of his neck thoughtfully as he glanced sidelong at Sam.

 

"Um," Sam said, his cheeks flushing pink. "Um, okay. Sure."

 

Dean clicked on the TV with the remote and punched in a numerical code on the prompt screen. Soon the screen was filled with the over-the-top moans and cries of the women of _Licking Lesbian Cheerleaders 3_ and Dean grinned over at Sam. "This okay?" he asked and Sam just nodded, eyes wide.

 

They watched in silence for a few minutes before Dean's hand slid down his thigh and he started stroking his leg before gradually finding his way to his dick.

 

Sam was watching Dean instead of the screen until the older teen took his hand off his growing erection and gestured to the naked women on the TV.  "You're supposed to watch the porn, Sammy."  Sam's eyes snapped back to the screen.

 

Slowly and shyly, each brother started stroking his dick, through the fabric of their sweatpants to begin with, and then with the elastic waists pulled down. The sharp slap of skin on skin filled their ears and after a few minutes of focused effort, Sam cried out, his hips stuttering as he came, streaks of come spraying over his stomach. He yelped as the pressure from the plug made the pleasure unbearable and another pulse of come erupted from his dick.

 

Tears sprang to Sam's eyes and Dean quickly stopped his own pleasure to check on Sam.

 

"Too much. It's too much," Sam was whining, his head lolled back against the back of the couch.

 

"Shh, it's okay, Sammy." Dean crouched between Sam's knees and stroked his younger brother's tear-streaked face. "That was maybe too much for your first time. Do you want to go take it out?"

 

"I can't," Sam sobbed. "I can't walk that far. Please, just take it out here, Dean. Please"

 

Dean's forgotten erection throbbed at the thought but he quickly tucked himself away, his need to help Sam overriding any of his own more base needs.

 

"Sure, thing, Sammy. Now, I need you to be brave for me and either roll onto your stomach or pull your knees up to your chest so I can get access."

 

Sam whined, but he rolled face-down on the couch, crying out, and then burying his face in the cushions. His sounds became piteous when Dean reached between his cheeks and gripped the base of the plug.

 

"Just breathe, Sammy," Dean soothed, stroking Sam's lower back. "Okay, on three. One." Dean pulled out the plug in a smooth motion, discarding it into a crumpled t-shirt on the floor and then stroked Sam's back again until the younger Winchester stopped swearing at him. He tried not to look at the pink gape and failed miserably, but he did manage to control himself enough that he didn't slip a finger inside the way he wanted to.

 

When Sam felt like he could walk again, Dean helped him to the bedroom and lay him on the lumpy bed. Sam grabbed Dean's hand as he was backing away.

 

"Stay?" Sam asked, his voice small, and there was no way for Dean to refuse.

 

"Fine. Move over. And no hogging the covers." He climbed into the bed behind his brother, closed his eyes, and focused on Sam's breathing until it lulled him to sleep.

  
  


****************

The brothers were sparring in a field several weeks later when Sam's reaction times were off. Way off. Dean was driving him relentlessly because he knew how much shit they'd both be in if John decided to test Sam and he performed this badly. He made a sweating, shaky Sam do the same maneuvers over and over until Dean was fed up with Sam's weak responses and he slammed Sam to the ground, landing on top of him, and pinning him hard.

 

Sam yelled and twitched beneath him and Dean kneeled up to discover a wet spot on the front of Sam's jeans.

 

"What the absolute fuck, Sam?" And then realization dawned on him. "Did you just come?  Holy shit. You're wearing it aren't you?"

 

Sam looked away, but then admitted that he was. He also confessed that the mornings when Dean had accused him of being especially pissy before school was because he'd been practicing wearing the plug.

 

Dean bit his lip. "Well, when you can pin me with that inside you, I'll buy you a bigger one."

 

Sam's eyes flashed darkly, and both brothers had to take extra-long showers after sparring practice that afternoon.

  
  


***************

 

Dean slipped Sam a small bag as they were packing up the car. John had returned late the night before and was in no mood for either boy to be dragging his heels, but Sam insisted he needed the bathroom one more time, and Dean hustled their father out to wait in the car.

 

When Sam climbed in the back seat, he winced, but then settled in. Dean grinned at him over his shoulder as John pulled out of the parking lot, kicking up gravel behind them. They were at least two hours out when Dean turned up the stereo and then thumbed a small dial in his pocket.

 

Sam jumped and spread his arms wide to brace himself on the seat, grunting as the unexpected vibration hit. John frowned at him in the rearview mirror.

 

"What's the problem, Son?"

 

"N-nothing, Sir," Sam answered. Thinking quickly, he added, "My stomach's just off this morning. Maybe a bad taco for dinner last night."

 

Dean winked over his shoulder at his brother, impressed with Sam's ability to think on his feet. He waited another half-hour before he turned the dial up a notch and Sam flailed out again. He clutched his stomach when John looked at him again. "Sorry, Dad. Cramps. Um, are we gonna stop soon? I could use a bathroom."

 

Dean answered, gesturing to the road sign ahead, "Looks like there's a stop about 20 miles ahead. Can you make it that far or do we need to find you some bushes?" He nudged the dial forward again and Sam whimpered.

 

"I think I can wait," Sam replied through gritted teeth, glaring at Dean.

 

Dean grinned back at him. "That's my Sammy. Always so tough."

 

John gave Dean a weird look and Dean just shrugged and started tapping along with the music, turning it up as You Shook Me All Night Long came on.  He messed with the dial a few times, turning it down then up again, hearing Sam grunt and twitch in the back seat.  When they were about five miles out, he cranked the vibrations and then put on his best concerned face as Sam whimpered, twitched, and contorted in the back seat.

 

Sam's eyes grew huge with panic and sweat was trickling down the sides of his face. He was fighting so hard, but the sensations were overwhelming and he couldn't stop it, curling into a ball as he came, flooding the inside of his shorts, and biting his lip hard enough to draw blood.

 

Dean turned the dial to off as soon as Sam came. He made soothing noises about how close they were to relief but Sam just groaned weekly and flipped Dean off as he slumped in the back seat.

  
  


Sam was out the door of the Impala the second they pulled into the gas station/diner, waddling awkwardly toward the washrooms. John headed straight to the restaurant but Dean hesitated.

 

"You go in. I'm just gonna take Sam a fresh pair of drawers and then meet you inside."  John gave him another odd look. "I've had food poisoning from tacos before, and he'll probably just want to burn the pair he's wearing."

 

John shuddered and shook his head. "It's good that you look out for your brother, Dean." He headed inside and Dean called after him as he fished a fresh pair of boxers out of Sam's duffel.

 

"Bacon cheeseburger, extra onions."

  
  
  


Dean knocked on the bathroom door. "Sammy, it's me. Open up. I've got you some fresh drawers."

 

Sam opened the door just a crack, reaching his hand out, but Dean pushed inside and locked the door behind him.  Sam was swearing a blue streak about what an asshole Dean was but Dean ignored him and pressed him hard against the door. He reached for Sam's undone jeans. "Lemme see. I gotta see. Please, Sammy."

 

Sam huffed out a sharp breath but when he looked into Dean's wide eyes, he nodded his assent. Dean pressed his hand to the outside of Sam's boxers, feeling the wetness soaking through the cotton. He groaned and leaned his head against Sam's shoulder. "You should have seen how fucking hot you were, how fucking perfect you were." He slid his hand into the waistband of Sam's shorts and Sam brought his hands up to grip Dean's shoulders, fingers digging into the muscle as Dean's fingers trailed through the mess of come, then gripped his rapidly refilling 15-year-old cock.

 

Sam's nimble fingers found Dean's fly, unzipped, and then he slid his hand into his brother's boxers, discovering that Dean's underwear were nearly as wet as his own from the moisture leaking from the tip of Dean's cock. Dean gasped and nuzzled the side of Sam's neck.

 

"We haven't got much time, Sammy. Can I?" Dean pressed his hips to Sam's and grabbed both of their cocks together, using the slick of Sam's previous release to smooth the way. Sam groaned as Dean jacked them together, grabbing Dean's ass and pulling him in even tighter. Dean buried his nose in the soft spot just behind Sam's ear and drank in Sam's essential scent as their cocks slid together through his fist.

 

"Oh, fuck," Sam cried out and Dean felt the pads of Sam's fingers dig into his ass cheek hard enough to bruise as the second orgasm in the past twenty minutes slammed into him. Dean wasn't far behind and he breathed into Sam's neck as he came hard against Sam's cock.

 

When he could breathe easily again, Dean pressed his forehead to Sam's and looked deeply into Sam's eyes.

 

"You okay, Sammy?"

 

"Yeah."

 

"You sure?"

 

"Yeah. But Dean? Do you think it's weird that we did this? We're brothers."

 

"It's weird," Dean admitted and Sam slumped a little. "But I don't wanna stop."

 

Sam grinned wide, his dimples popping. "Good, 'cuz I don't wanna stop either."

 

 

**_Comments are pie. Please feed me delicious pie by commenting. Thanks!_ **

 

 


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